1. Field of the Invention
The present invention relates generally to centrifugal superchargers for providing increased airflow to an engine. More particularly, the present invention concerns a velocity variance reducing multiple bearing arrangement for effectively rotatably supporting the high speed impeller shaft of a supercharger, thereby extending bearing life without compromising shaft speed.
2. Discussion of Prior Art
A centrifugal supercharger traditionally has a high speed impeller shaft rotatably supported on the supercharger by two, spaced apart, ball bearings. Given the high rotational speeds of the impeller shaft, commercially available bearings are typically not rated high enough to withstand the demands of a supercharger. Accordingly, the bearing will be operating outside of its manufacturer recommended limits. That is, there is a substantial risk of bearing failure, thereby limiting the overall life span of the supercharger.
In response to this undesired limiting risk, some superchargers utilize paired bearings, i.e. two bearings located in close proximity to one another relative to the shaft, (four total bearings) in place of the single bearings, with each pair spaced apart from the other pair. This, however, only offers redundancy and while this may offer some slight increase in bearing life, it is still limiting. This paired arrangement also has the added disadvantage of a cumulative tolerance effect, or too much xe2x80x9cslopxe2x80x9d for many high precision applications.
Responsive to these and other problems, an important object of the present invention is to provide a supercharger that is capable of providing relatively high amounts of airflow (e.g., 1800 gasoline horsepower). It is also an important object of the present invention to provide a supercharger that has improved durability yet maintains a high load capacity relative to conventional superchargers. In this regard, an important object of the present invention is to provide a long-life bearing arrangement for a supercharger capable of generating the desired horsepower increases. In addition, an important object of the present invention is to provide a bearing arrangement that has virtually no limiting effect on the boost provided by the supercharger. Another important object of the present invention is to provide a supercharger having a bearing arrangement that assuredly provides sufficient and effective rotatable support to the high speed impeller shaft. Yet another important object of the present invention is to provide a supercharger having a durable, simple and inexpensive construction.
In accordance with these and other objects evident from the following description of the preferred embodiments, the present invention concerns a supercharger having a case, a rotatable impeller, a high speed shaft drivingly coupled between the impeller and a power source, and a multiple bearing arrangement rotatably supporting the shaft on the case. The bearing arrangement includes a shaft bearing and a case bearing, each of which includes relatively rotatable inner and outer races. The inner race of the shaft bearing is fixed relative to the shaft. The outer race of the case bearing is fixed relative to the case. The outer race of the shaft bearing and inner race of the case bearing are fixed relative to one another. It is believed that such an arrangement reduces the variances in the velocities of the positive contact points of the bearings, thereby reducing skidding, maximizing both load and speed, and increasing bearing life. In this manner the present invention provides a supercharger having improved bearing life and same or equal horsepower capacity, while permitting the use of relatively traditional bearings that have been simply and inexpensively modified.
The present invention also involves the use of this bearing arrangement in other applications.